1. Field of the Invention
The present invention relates generally to round balers and, more particularly, to an improved bale shape monitor for facilitating uniform bale formation by the baler.
2. Discussion of Prior Art
In most instances, the crop windrow picked up by a round baler tends to be narrower than the overall length of the baling chamber. The baler must consequently be steered left and right as it pulled across the field so that an equal amount of crop material is delivered along the length of the chamber during the bale cycle; otherwise, the baler will likely form an asymmetrical bale having an uneven diameter from one end to end the other end. For example, if the baler is positioned relative to the windrow so that a disproportionate amount of crop is delivered to the left end of the baling chamber, the bale will almost definitely have a conical shape, with the left end of the bale having a greater diameter and density than the right end. In any case, nonuniform bale formation results in unsightly bales that are difficult to sell, stack and tie. Moreover, nonuniform bale formation often damages or, at the very least, places undue wear on the bale forming components.
Even the most skillful baler operator has difficultly in tediously weaving the baler from side to side for ensuring even delivery of crop material between the sidewalls of the baler. Accordingly, bale shape monitors have been developed to assist the operator with uniform bale formation. Conventional bale shape monitors typically include indicators placed within the cab of the tractor to signal to the operator when the bale is not being properly shaped. Traditional indicators include bale shape displays which represent the shape of the bale from end-to-end or at certain locations along the length of the bale. A more common indicator includes so-called "driving lights" which signal to the operator when to steer left, steer right or simply drive forward. Additionally, some balers have even been equipped with a steering mechanism for automatically steering the baler left and right in response to the bale shape sensed by the monitor.
The indicators mentioned above are traditionally operated by one or more sensors on the baler. In round balers having an expandable baling chamber defined in part by a plurality of endless elements (e.g., a belt-type baler), the sensors are associated with the endless elements adjacent the sidewalls of the baler. Each end sensor is often positioned along a stretch of the corresponding element to detect when the stretch becomes slackened. It will be appreciated that the elements are traditionally tensioned by a single slack takeup mechanism, and accordingly, slackening of one of the elements relative to the remaining elements indicates that the area of the baling chamber bound by the one element is receiving less crop material than the others. Alternatively, the ends sensors are positioned along stretches of the elements defining the baling chamber so as to directly sense the diameter of the bale. The operator may consequently steer the baler left or right depending upon the diameter of the bale sensed adjacent the ends thereof.
However, these known expedients are problematic. Particularly, conventional bale shape monitors have complex and relatively expensive constructions. Additionally, a number of conventional monitors are not dependable and do not accurately sense the shape of the bale. For example, with monitors having a sensor for detecting the slack condition of one of the endless elements, the shape of the bale may not be accurately detected because of uneven stretching between the elements. Moreover, no baler has heretofore been provided with a monitor which effectively compares the diameter of the bale adjacent the ends thereof to the diameter of the bale at an intermediate location spaced between the ends, so that the operator is signaled when the ends are deficient relative to the middle of the bale. As will subsequently be described, this significantly simplifies the construction of the monitor and more accurately detects bale shape to improve uniform bale formation.